Apparatus for extruding multi-component liquid filaments

ABSTRACT

An apparatus for extruding multiple types of liquid materials into multi-component filaments. A pair of outer manifold elements sandwich an intermediate manifold element. Respective channels are formed between opposing sides of the outer manifold elements and the respective opposite sides of the intermediate manifold element. These recesses form channels which diverge or widen away from associated inlets at the top of the manifold assembly. A die tip is coupled to the manifold assembly at a lower side and communicates with the outlets of the channels. The die tip includes a combining member for producing a desired multi-component filament configuration.

This application relates to U.S. application Ser. No. 09/702,387,assigned to the assignee of the present invention and filed on even dateherewith. The disclosure of this related application is fullyincorporated herein by reference.

FIELD OF THE INVENTION

The present invention generally relates to apparatus for extrudingthermoplastic filaments and, more particularly, apparatus forspunbonding multi-component filaments.

BACKGROUND OF THE INVENTION

Spunbonding or other techniques for extruding fine diameter filamentsfind many different applications in various industries including, forexample, in nonwoven material manufacturing. This technology generallyinvolves extruding a thermoplastic material from multiple rows ofdischarge outlets extending along the lower surface of an elongatespinneret. Spunbonded materials are used in such products as diapers,surgical gowns, carpet backings, filters and many other consumer andindustrial products.

The machines for spunbonding such materials can be very large with thefilament discharge outlets numbering in the thousands.

For certain applications, it is desirable to utilize multiple types ofthermoplastic liquid materials to form individual cross-sectionalportions of each filament. Often, these multi-component filamentscomprise two components and, therefore, are referred to as bicomponentfilaments. For example, when manufacturing nonwoven materials for use inthe garment industry, it may be desirable to produce bicomponentfilaments having a sheath-core construction. The sheath may be formedfrom a softer material which is comfortable to the skin of an individualand the core may be formed from a stronger, but perhaps less comfortablematerial having greater tensile strength to provide durability to thegarment. Another important consideration involves cost of the material.For example, a core of inexpensive material may be combined with asheath of more expensive material. For example, the core may be formedfrom polypropylene or nylon and the sheath may be formed from apolyester or co-polyester. Many other multi-component fiberconfigurations exist, including side-by-side, tipped, and microdenierconfigurations, each having its own special applications. Variousmaterial properties can be controlled using one or more of the componentliquids. These include, as examples, thermal, chemical, electrical,optical, fragrance, and anti-microbial properties. Likewise, many typesof die tips exist for combining the multiple liquid components justprior to discharge or extrusion to produce filaments of the desiredcross-sectional configuration.

One problem associated with multi-component extrusion apparatus involvesthe cost and complexity of the manifolds used to transmit each of theseparate component liquids to the multi-component die tip. Typicalmanifolds must be machined with many different passages leading to thedie tip to ensure that the proper flow of each component liquid reachesthe die tip under the proper pressure and temperature conditions. Thesemanifolds are therefore relatively complex and expensive components ofthe multi-component extrusion apparatus.

For these reasons, it would be desirable to provide multicomponentextrusion apparatus having a manifold system which may be easilymanufactured and yet fulfils the requirement of effectively transmittingeach of the component liquids to the multi-component die tip.

SUMMARY OF THE INVENTION

The present invention therefore provides an apparatus for extrudingmultiple types of liquid materials into multi-component filamentsincluding a unique manifold structure coupled with a multi-component dietip. Generally, the invention pertains to melt spinning apparatus, suchas spunbonding and meltblowing apparatus. The preferred or illustrativeembodiment specifically disclosed herein relates to a spunbondingapparatus. In one general aspect, the apparatus comprises anintermediate manifold element having first and second opposite surfaces.First and second outer manifold elements respectively couple to thefirst and second opposite surfaces and have respective opposed surfaces.Each opposed surface respectively abuts one of the first and secondopposite surfaces of the intermediate manifold element. A first channelis formed between the opposed surface of the first outer manifoldelement and the first opposite surface of the intermediate manifoldelement. A second channel is formed between the opposed surface of thesecond outer manifold element and the second opposite surface of theintermediate manifold element. The first and second channels have inletsfor respectively receiving the first and second liquids and outlets forrespectively discharging the first and second liquids. These inlets andoutlets may be formed in the intermediate manifold element, in the outermanifold elements, or between the intermediate manifold element and therespective outer manifold elements. The first and second channels maycomprise recesses formed in the first and second opposite surfaces ofthe intermediate manifold element, or recesses formed in the opposedsurfaces of the first and second outer manifold elements, or anycombination thereof which forms the necessary channels.

A die tip is coupled adjacent the manifold elements. The die tipincludes a plurality of multi-component filaments discharge outlets andat least first and second liquid distribution passages. The first andsecond liquid distribution passages are adapted to receive the first andsecond liquids respectively from the outlets of the first and secondchannels. A liquid combining member communicates between the first andsecond liquid distribution passages and the filament discharge outlets.The liquid combining member is configured to receive the first andsecond liquids and combine the first and second liquids into respectivemulti-component filaments.

In a more specific preferred embodiment of the manifold structure, thefirst and second outer manifold elements have respective recesses and,more preferably, a plurality of recesses on their respective opposedsurface. The intermediate manifold element is coupled between therespective opposed surfaces of the first and second outer manifoldelements. The recesses on the respective first and second oppositesurfaces of the intermediate manifold element communicate, andpreferably align with corresponding recesses on the opposed surfaces ofthe first and second outer manifold elements. The communicating recessestogether form at least first and second channels and, preferably, firstand second pluralities of channels each having a liquid inlet and aliquid outlet communicating with the die tip on the opposite sides ofthe intermediate manifold element.

Various advantages, objectives, and features of the invention willbecome more readily apparent to those of ordinary skill in the art uponreview of the following detailed description of the preferredembodiments, taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded perspective view of a multi-component spunbondingapparatus constructed in accordance with a preferred embodiment of theinvention.

FIG. 2 is a cross section taken along line 2—2 of FIG. 1, butillustrating the manifold elements and die tip in assembled condition.

FIG. 3 is an enlarged view of the die tip shown in FIG. 2.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to FIGS. 1 and 2, a spunbonding apparatus 10 constructed inaccordance with the inventive principles includes first and second outermanifold elements 12, 14. An intermediate manifold element 16 is coupledbetween outer manifold elements 12, 14 in sandwiching relation. A dietip or spin pack assembly 18 is coupled to outer manifold elements 12,14 and intermediate manifold element 16 by fastener assemblies 20.Threaded fasteners (not shown) are inserted through holes 22, 24 in therespective outer manifold elements 12, 14 and thread into internallythreaded holes 26 contained in intermediate manifold element 16.Although only holes 26 are shown, it will be appreciated that theopposite side of manifold element 16 has similar threaded holes. Aliquid supply block 30 is mounted to an upper surface of intermediatemanifold element 16 and includes a plurality of pumps 32 a, 32 b forrespectively pumping first and second types of liquid, such asthermoplastic material. The first type of liquid is pumped into eachinlet 40 and the second type of liquid is pumped into each inlet 42 inthe top of intermediate manifold element 16. Although three sets ofpumps 32 a, 32 b are shown in this preferred embodiment, it will beunderstood that a greater or fewer number of pump sets 32 a, 32 b may beprovided instead. Alternatively, other manners of supplying manifolds12, 14, 1 6 with multiple types of liquids may be employed instead. Inaddition, the side-by-side manifold concepts of this invention may beemployed to form filaments from more than two component liquids.

As shown best in FIG. 2, outer manifold elements 12, 14 includerespective opposed notches 44, 46 communicating with liquid supplyinlets 40, 42. Corresponding notches 48, 50 are formed in opposite sidesurfaces of intermediate manifold element 16 such that respectivechannels 52, 54 are formed for receiving the component liquids frominlets 40, 42. Recesses 56, 58 are formed in opposed sides of outermanifold elements 12, 14 and align with corresponding recesses 60, 62formed on opposite sides of intermediate manifold element 16. Thesealigned recesses form respective channels 64, 66 which communicate atrespective upper ends thereof with channels 52, 54 and which furtherinclude discharge outlets 70, 72 at lower ends thereof. It will beappreciated that channels 64, 66 may instead be formed by recessesformed only on intermediate manifold element 1 6 or only on outermanifold elements 12, 14 and, in that case, the abutting manifoldelement will serve as a cover plate. As appreciated from FIG. 1, eachchannel 64, 66 formed respectively between recesses 56, 60 and recesses58, 62 diverges or widens in a lengthwise direction relative to thelengthwise extents of manifold elements 12, 14, 16 from inlet channels52, 54 to outlets 70, 72.

Referring to FIGS. 2 and 3, die tip 18 more specifically comprises aconventional spin pack assembly. The details of assembly 18 are morespecifically disclosed in U.S. Pat. No. 5,562,930, the disclosure ofwhich is hereby incorporated by reference in its entirety. Generally,die tip 18 comprises a top plate 80, a screen support plate 82, ametering plate 84, an etched distributor plate 86 and a spinneret plate88 held together by fasteners 90. The respective first and secondliquids enter slots 100, 102 10 formed on the upper surface of top plate80 from outlets 70, 72 of channels 64, 66. The first and second liquidsthen enter a series of passages 104 and a series of passages 106communicating with respective cavities 108, 110. The two liquids thenrespectively travel through filters 112, 114 and enter liquid componentslots 116, 118. Slot 116 communicates with holes 120 and slot 118communicates with holes 122. One of several slots 124 is shown in FIGS.2 and 3 for receiving one of the two component liquids from hole 120 orhole 122. Although not shown in the drawings, another alternating seriesof slots is provided for the other component liquid. Apertures 128 areprovided for the first component liquid and apertures 130 are providedfor the second component liquid in metering plate 84.

The etched distributor plate 86 receives the mutually separatedcomponent liquids and combines these liquids in the desired manner asthe liquids reach the discharge passages 140. The multi-componentfilaments are then discharged through outlets 142. Holes 160 or 162located along the length of each outer manifold element 12, 14 receiveheater rods for heating the two liquids and the process air to anappropriate application temperature. Temperature sensing devices (notshown), such as RTD's or thermocouples are also placed in manifoldelements 12, 14 to control the temperature. A more complete descriptionand operation of the die tip or spin pack 18 may be found in the aboveincorporated U.S. Pat. No. 5,562,930. In addition, it will beappreciated that many other die tip assemblies may be used forspunbonding applications or other multi-component filaments extrusionapplications and that this disclosure is merely illustrative of onepreferred configuration.

While the present invention has been illustrated by a description ofvarious preferred embodiments and while these embodiments has beendescribed in some detail, it is not the intention of the Applicant torestrict or in any way limit the scope of the appended claims to suchdetail. Additional advantages and modifications will readily appear tothose skilled in the art. The various features of the invention may beused alone or in numerous combinations depending on the needs andpreferences of the user. This has been a description of the presentinvention, along with the preferred methods of practicing the presentinvention as currently known.

However, the invention itself should only be defined by the appendedclaims, wherein I claim:
 1. An apparatus for extruding at least firstand second liquid materials into multi-component filaments, comprising:first and second outer manifold elements having respective opposedsurfaces, each outer manifold element including a recess on itsrespective opposed surface, and an intermediate manifold element coupledbetween said respective opposed surfaces of said first and second outermanifold elements, said intermediate manifold element having first andsecond liquid supply inlets for receiving the first and second liquidmaterials, and having first and second opposite surfaces each having arecess, said recesses on said first and second opposite surfacesrespectively communicating with said recesses on said opposed surfacesto form first and second channels, said first and second channels influid communication with said first and second liquid supply inlets andhaving outlets for respectively discharging the first and second liquidmaterials, a die tip coupled to said outer manifold elements and saidintermediate manifold element, said die tip including a plurality ofmulti-component filament discharge outlets, at least first and secondliquid distribution passages adapted to receive the first and secondliquid materials respectively from said outlets of said first and secondchannels, and a liquid combining member communicating between said firstand second liquid distribution passages and said filament dischargeoutlets, said liquid combining member configured to receive the firstand second liquid materials and combine the first and second liquidmaterials into respective multi-component filaments, and first andsecond pumps mounted to said intermediate manifold element, said firstpump configured to supply the first liquid material to said first liquidsupply inlet and said second pump configured to supply the second liquidmaterial to said second liquid supply inlet.
 2. The apparatus of claim1, wherein said channels extend along lengthwise portions of saidmanifold elements and each channel widens along its associatedlengthwise portion in a direction from its respective inlet toward itsrespective outlet.
 3. The apparatus of claim 2, further comprising aplurality of said channels respectively formed by a plurality of saidrecesses on said opposite sides of said intermediate manifold elementand on said opposing sides of said outer manifold elements. 4.Theapparatus of claim 1, further comprising a plurality of said channelsrespectively formed by a plurality of said recesses on said oppositesides of said intermediate manifold element and on said opposing sidesof said outer manifold elements.